Loud speaker systems



Sept. 15, 1959 D. A. LYONS LOUD SPEAKER SYSTEMS Filed 'Jan. 8; 1958United States Patent LOUD SPEAKER SYSTEMS Douglas Arthur Lyons, London,England Application January 8, '1958, Serial No. 707,728

Claims priority, application Great Britain January 11, 1957 2 Claims.(Cl. 18131) This invention relates to loud speaker systems and moreparticularly to a loud speaker system of the kind comprising a bank ofspeaker elements respectively having speaker cones arrangedrectilinearly with their axes parallel or substantially parallel. When aloud speaker system of the kind described is vertically disposed theresultant omitted beam of sound spreads horizontally rather thanvertically and sound can be adequately received at points comparativelywidely spaced horizontally with respect to the speaker bank. However,the beam of sound emitted from such a bank of speaker elements suffersfrom two main disadvantages. On the one hand the intensity of the soundfalls away as one moves from the centre to either side of the beam andon the other hand the high frequency sound content at the sides of thebeam is appreciably lower than that at the centre of the beam.

It is an object of the invention to provide an improved loud speakersystem. A further object of the invention as applied to a loud speakersystem of the kind specified is to provide a beam of sound in which thedistribution of frequencies and intensity is of improved uniformity.

According to the present invention a loud speaker system comprises abank of speaker elements respectively having speaker cones arrangedrectilinearly with the axes thereof substantially parallel, an elongatedcasing within which the speaker cones are mounted, a baffie in the formof a channel-shaped strip which is V-shaped and of uniform depth incross-section and is mounted at opposite ends thereof on the casingforwardly of and symmetrically with respect to the speaker cones so asto extend diametrically across each speaker cone of the bank, the bafllebeing of such depth that it is adapted to deflect a central section onlyof a beam of sound emitted from the bank outwardly towards oppositesides of the beam.

Speaker systems of the kind described are particularly useful forbeaming sound to specific locations where difficulties in hearing areexperienced by virtue of the presence of extraneous noises. For examplesuch systems are finding increasing use in passenger aircraft andrailway carriages. It has been found that by placing vertically disposedspeaker banks each provided with a baflle according to the invention atopposite ends of a railway carriage or passenger compartment of anaircraft, adequate sound reception can be obtained at all points in thecarriage or compartment.

The invention will now be described, by way of example, with referenceto the accompanying, diagrammatic drawings, in which:

Patented Sept. 15, 1959 Fig. 1 is a perspective view of one form of theinvention, and

Fig. 2 is a view as seen looking from below Fig. 1.

Referring to the drawings, within an elongated rectangular frame orcasing 1 are disposed speaker elements each having a speaker cone 2mounted on an apertured rectangular plate 3 which is suitably secured bymeans (not shown) to a rear face 4 of a front wall 5 of the casing 1.Between the wall 5 and the plates 3 of the speaker elements is provideda grill 6 of expanded metal or other suitable material and the grill 6is arranged to cover an elongated aperture 7 formed in the front wall 5of the casing.

The speaker elements are connected in parallel electrical relationshipwith terminals 8 so that the speaker bank can be connected to a poweramplifier.

On a forward face 9 of the casing front wall 5 is mounted a V-shapedbaflle 10 which extends centrally along the aperture 7 and isappropriately secured at opposite ends thereof, for example, by rivets11 to the wall 5. The baffle 10 which is of uniform cross section thusextends diametrically across the front of and normal to the axis of eachspeaker cone 2. Side walls 12 of the baflie 10 are equally inclined tothe axis of each speaker cone 2 and the angle between the side walls 11is degrees or less so that sound reflected by the baffle is not directedrearwardly into the speakers.

In operation, a central part of the beam of sound emitted by the speakerbank is deflected outwardly by the baflle side walls 12 and the overalleffect is to produce a beam of sound the lateral intensity of which isof improved uniformity whilst the quality of sound at the sides of thebeam is also improved.

I claim:

1. A loud speaker system comprising a bank of speaker elementsrespectively having speaker cones arranged rectilinearly with the axesthereof substantially parallel, an elongated casing within which thespeaker cones are mounted, a bafiie extending diametrically across eachspeaker cone and longitudinally of said bank, said bafile being V-shapedand uniform in cross-section, the apex of said V being directed towardsaid speaker cones and the distance between the remote ends of saidV-shaped baflle being substantially less than the diameter of saidspeaker cones, the baflie being of such depth that it is adapted todeflect a central section only of a beam of sound emitted from the bankoutwardly towards opposite sides of the beam.

2. A loud speaker system as set forth in claim 1 in which the anglebetween the sides of the V-shaped bafile is not greater than 90.

References Cited in the file of this patent UNITED STATES PATENTS2,020,166 Swinyard Nov. 5, 1935 FOREIGN PATENTS 695,239 France Sept. 29,1930 870,882 France Ian. 3, 1942 538,458 Italy Jan. 25, 1956

